Prior to the present invention, as shown by Thompson et al. U.S. Pat. No. 3,723,566, organosiloxane polyamide block polymers were made by effecting reaction between lactam and organosiloxane having at least one substituent containing an N-acyl lactam group or a functional group effective in initiating the polymerization of lactam.
In copending application of Policastro et al., Ser. No. 706,374, filed Feb. 27, 1985, U.S. Pat. No. 4,603,177, for Silicone-Lactam Blends and Products Obtained Therefrom, a method is described for making cross-linked polyamide by using certain lactam promoters having silicon attached to the lactam nitrogen by silicon-nitrogen linkages. Although the silicone-polyamides or silicon containing crosslinked polyamides have been found to provide a variety of useful products, these materials are inherently subject to oxidative instability as a result of the presence of silicon alkylene linkages between organosilicon blocks and polyamide blocks.
The present invention is based on the discovery that silicone-polyamide block polymers having interconnecting silicon arylene linkages can be made by effecting reaction between lactam and organosilicon material having chemically combined groups of the formula ##STR1## where R is a divalent C.sub.(6-14) arylene hydrocarbon radical or substituted C.sub.(6-14) divalent arylene hydrocarbon radical. The resulting silicone-polyamide block polymers can be used as molding compounds, encapsulants, tough rubbers, coatings, adhesives and thermoplastic property modifiers.